I direct drive it from either 3 123A surefire batteries (draws 1.4 amps & VERY bright) or 6 AA Ni-Mh rechargable in 2 3AA>D adaptors (still bright (draws .8 amps) and gets long, guilt free run time), To top it of I put a Glass "Ultra Clear Lens" (99% of light transmitance Vs 88% for the stock mag lens) and made a Sputtered Reflector to smooth out the beam and make it Surefire like. Of all, this is my very favorite mod.
In the beam shot it I used a SureFire G2 with a P-60 Lamp, but a P-61 Lamp more closly match's in brightness and throw. the Mag throws a bit farther though and is MUCH Whiter even as the Batteries die it stays white ( and ok so the 5 watter is a bit brighter to:-))